zoj 3775 ?!

#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <queue>#include <algorithm>#include <stack>using namespace std;char s[1000];int main(){    int n;    int xia,gan;    cin >> n;    getchar();    while(n--)    {        gets(s);        int len = strlen(s);        xia = gan = 0;        for(int i = 0; i<len; i++)        { if(s[i] == '_')     xia++; else if(s[i] == '!')     gan++;        }        if(xia>1) printf("Non");        else if(xia == 1 && !gan) printf("Yesn");        else if(xia && gan) printf("Non");        else        { int l; char str[20]; if(len%13) {     printf("Non"); } else if(len == 13) {     if(!strcmp(s,"Hello, world!"))         printf("Yesn");     else         printf("Non"); } else {     int flag = 1;     for(int i = 13; i<=len-13; i+=13)     {         if(s[i] == 'H' && s[i+1] == 'e' && s[i+2] == 'l' && s[i+3] == 'l' && s[i+4] == 'o' && s[i+5] == ',' && s[i+6] == ' ' && s[i+7] == 'w' && s[i+8] == 'o' && s[i+9] == 'r' && s[i+10] == 'l' && s[i+11] == 'd' && s[i+12] == '!')  flag == 1;         else         {  flag = 0;  break;         }     }     if(flag)         printf("Yesn");     else         printf("Non"); }        }    }    return 0;}